Backup horror stories: Rendering error in the global navigation tab

Chances are that if you're restoring a site collection from backup, something has gone seriously wrong.  Naturally, at this point, you've had just about enough of unexpected glitches, and you REALLY don't want anything to look weird once you restore and load up the site again.  Oh, but Mr. Murphy is there laying down the law, and all you see on the global nav is a big "Error" tab.  Terrified, you mouse over it with a morbid curiosity, only to discover the following error in a tooltip:

An error occured while rendering navigation for requested URL: /. Exception message: Object reference not set to an instance of an object. Stack trace:    at Microsoft.SharePoint.Publishing.PublishingWeb.<>c__DisplayClass2d.<CleanupInternalIDs>b__2c()
   at Microsoft.SharePoint.SPSecurity.CodeToRunElevatedWrapper(Object state)
   at Microsoft.SharePoint.SPSecurity.<>c__DisplayClass4.<RunWithElevatedPrivileges>b__2()
   at Microsoft.SharePoint.Utilities.SecurityContext.RunAsProcess(CodeToRunElevated secureCode)
   at Microsoft.SharePoint.SPSecurity.RunWithElevatedPrivileges(WaitCallback secureCode, Object param)
   at Microsoft.SharePoint.SPSecurity.RunWithElevatedPrivileges(CodeToRunElevated secureCode)
   at Microsoft.SharePoint.Publishing.PublishingWeb.CleanupInternalIDs(PublishingWeb pubwebToCleanUp)
   at Microsoft.SharePoint.Publishing.PublishingWeb.get_PagesList()
   at Microsoft.SharePoint.Publishing.CachedArea.GetChildPageIds()
   at Microsoft.SharePoint.Publishing.Navigation.PortalSiteMapProvider.UserHasRightsToCachedObject(CachedObject cachedObject, SPWeb currentContext)
   at Microsoft.SharePoint.Publishing.Navigation.CachedObjectSiteMapNode.IsAccessibleToUser(SPWeb contextWeb)
   at Microsoft.SharePoint.Publishing.Navigation.PortalSiteMapNode.GetNavigationChildren(NodeTypes includedTypes, NodeTypes includedHiddenTypes, OrderingMethod ordering, AutomaticSortingMethod method, Boolean ascending, Int32 lcid)
   at Microsoft.SharePoint.Publishing.Navigation.PortalSiteMapNode.GetNavigationChildren(NodeTypes includedHiddenTypes)
   at Microsoft.SharePoint.Publishing.Navigation.PortalSiteMapProvider.GetChildNodes(PortalSiteMapNode node, NodeTypes

Of course I can't speak for everyone in every situation, but this kind of thing late at night when everything else has hit the fan...  it's enough to make you want to swap careers with Old MacDonald (seriously, what kind of farm grows moss?).

But enough about my midnight work hallucinations.  At this point, the most helpful thing to do -- assuming you still have that backup -- is to delete the site collection entirely.  Go into Central Admin, click Application Management, and blow that site collection away.  THEN go back and restore from backup again.

If that doesn't work, then run the Config Wizard again; that'll usually shake something loose.